Annette Bening and Jamie Bell say their mutual affection for the man behind “Film Stars Don’t Die In Liverpool” brought an added dimension to their roles.

The movie is based on the 1986 memoir of the same name by Peter Turner, a Liverpudlian actor from a working class background who fell in love Oscar winner Gloria Grahame, a faded Hollywood film star nearly 30 years his senior.

“I think the most important thing was that I totally understood why she would fall in love with him. He’s lovable,” said four-time Oscar nominee Bening, seated alongside Bell during a roundtable interview at the Toronto International Film Festival last September.

“There isn’t a lot about Gloria that we know for sure. The stuff we do know is very scandalous about all of her marriages and her tempestuous life. But I imagine Peter having been unusually caring as a boyfriend for her.”

Bell said Turner’s love for and protectiveness over Grahame — who died of cancer in 1981 — was evident in the way he recounted stories of her and their time together.

“An hour and a half of talking to him you can see that he’s actually exhausted. It was at that point that I knew how important this relationship was to him and how much he loved her, that I had to kind of bring that to the film just as much.”

Grahame won the best supporting actress Oscar in 1953 for her role in “The Bad and the Beautiful,” and had star turns in 1950s film noir vehicles including “In a Lonely Place” with Humphrey Bogart and “The Big Heat” opposite Glenn Ford. But as the years passed she fell on hard times, working on smaller-scale theatre productions in the U.K. in her 50s.

“There is a certain dignity to her in her own way,” Bening said.

“She really struggled in finding work. But I think she had a certain grit about her. You just get on with it and take the work that you can find.”

The film, like Turner’s memoir, criss-crosses through time, from the chance meeting at a London guesthouse where the duo were both living, through their whirlwind trans-Atlantic love affair.